Ask the master gardeners

Sep. 20, 2008

Q: I would like to harvest seeds from my grandmother's climbing sweet peas and some of her other old-fashioned perennials so my sister and I can plant them at our homes. What is the best method?

A: The climbing perennial sweet pea to which you refer (Lathyrus Latifolius) is an old-fashioned import from Europe. It is in the pea (Fabaceae) family and it fixes nitrogen into the soil as well, so it is a good choice to amend your garden soil and to provide lovely cut flowers and a beautiful climbing accent for a trellis or fence.

To harvest the seeds, allow the pods to dry on the vine, then carefully pick the pods and store in a paper bag for several weeks until they are completely dry.

Unlike most seeds, peas and beans prefer to be kept in a place with air circulation, so after removing the debris from the pods, keep them in a container labeled with the name of the plant and the harvest date in a cool, dry place.

Plant them in the very early spring in a sunny spot in good garden soil. These seeds do not transplant well, so start them directly in the soil. They can become invasive if not thinned occasionally or if not cut back and cleaned up in the fall.

You do not say what other seeds you plan to harvest from Grandma's garden, but for most perennial seeds you would let the flower head dry on the plant, carefully cut the head and put it in a paper or fine mesh bag to air-dry in an area with less than 20 percent humidity and a temperature of about 70 degrees.

When dry, seal them in a labeled foil packet. Store in an airtight container in a cool, dry place for next season.